1 nerves of upper extremity

NERVES OF UPPER EXTREMITY

MAJ DR POONAM SINGHDEPT OF ANATOMY

NAIHS

OBJECTIVES

ORIGIN, ROOT VALUE, COURSE, BRANCHES AND APPLIED OF MAJOR NERVES OF UPPER EXTREMITY

BRACHIAL PLEXUS- imp nerves

BRACHIAL PLEXUS: NERVES

DISTRIBUTION OF MAIN NERVES

– AXILLARY – • Deltoid & Teres minor

– MUSCULOCUTANEOUS –• Muscles of Anterior Compartment of arm (flexors)

– MEDIAN –• Most of the Flexor muscles of forearm & Intrinsic

muscles in hand- labourer

– ULNAR – • FCU & part of FDP (forearm) and Intrinsic muscles

in hand- musician

– RADIAL –• Innervates all Extensor muscles of arm & forearm

MUSCULOCUTANEOUS NERVE

MUSCULOCUTANEOUS NERVE – Arise opposite lower border of Pectoralis Minor. – Derived from C5-C7 cervical ventral rami

Course : Supplies Coracobrachialis and then

pierces it. Descends laterally between Biceps and

Brachialis to lateral side of arm. Just below elbow it pierces deep fascia. Continues as lateral cutaneous nerve of

forearm..

– Supplies –

Coracobrachialis, Biceps and most of Brachialis. Branch to Brachialis

supplies Elbow joint.Br to humerus via

nutrient art

LESIONS OF MUSCULOCUTANEOUS NERVE

Commonest causes

– Isolated lesion is rare.

– injuries to • upper arm and • shoulder including

fracture of humerus.

LESIONS OF MUSCULOCUTANEOUS NERVE

Symptom and sign– Marked weakness of elbow flexion

• because of paralysis of – biceps brachii and much of – brachialis

– Sensory impairment • on the extensor aspect of the forearm in the distribution of

lateral cutaneous nerve of the forearm.

AXILLARY NERVE

AXILLARY (CIRCUMFLEX) NERVE – From posterior cord (C5 - C6) .

– Posterior to Axillary artery (3rd part) and anterior to Subscapularis,

– Above posterior circumflex

humeral vessels, traverses quadrangular space.

– Axillary trunk supplies a branch to shoulder joint.

BRACHIAL PLEXUS- POST CORD Axillary N cont’dDivides into

• anterior and • posterior branches.

Anterior branch along posterior circumflex humeral vessels, curves behind the humeral neck,

Supplies– Deltoid (deep to). – skin over its middle part.(cutaneous branches which pierce the

muscle)

Posterior branch

Anterior br of Axillary Nerve

Posterior branch supplies

– Teres minor» Branch to Teres minor has a pseudoganglion

– posterior and lower part of Deltoid. – upper part of long head of Triceps– upper lateral cutaneous nerve of arm

• Commonest causes• Dislocations of shoulder• Fractures of upper end humerus• Misplaced injections into deltoid

• Symptom and sign

• Wasting and weakness of Deltoid- • abduction of shoulder affected.

• sensory loss on outer aspect of upper arm below acromion.

LESIONS OF AXILLARY NERVE

MEDIAN NERVE

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MEDIAN NERVE

• Formed by two roots:– Medial & Lateral roots

• Contribution from both cords– Medial Root -

• derived from Medial cord, C8 & T1

– Crosses downward and laterally infront of 3rd part of Axillary and join Lateral root)

– Lateral root – • continuation of lateral cord, C5

to C7

• Supplies flexors of forearm• Labourer’s Nerve• Thickest nerve of Brachial

Plexus

FORMATION

• Formed in Axilla• lateral to 3rd part of Axillary artery

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MEDIAN NERVE: COURSE

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In arm-

Nerve descends lateral to Brachial artery

In middle of arm crosses in front of

artery runs on its medial side

to Cubital fossa

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At elbow-

lies deep to Bicipital aponeurosis

in front of Brachialis

Medial to Brachial art

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MEDIAN NERVE: COURSE

Forearm ─ Enters forearm

─ Bt two heads of Pronator Teres

─ Then passes deep to tendinous bridge ─ (formed by humero-ulnar &

radial heads of FDS)

─ Descends bt ─ FDS & FDP in forearm

─ 5 cm above Flexor

retinaculum ─ emerges from behind lateral

edge of FDS

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passes deep to tendinous bridge of FDS

─formed by humero-ulnar & radial heads of FDS

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Descends between

─ FDS & FDP in forearm

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5 cm above Flexor retinaculum

─ emerges from behind lateral edge of FDS

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MEDIAN NERVE: COURSEwrist – becomes

superficial– bt FDS & FCR

tendons)

– Passes deep to flexor retinaculum to enter palm

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BRANCHESIN ARM1. Vascular brs (symp twigs ) to brachial artery2. Branch to pronator teres above elbow

IN FOREARM3. Muscular brs

a). Trunk of median nv Flexors of forearm except FCU & medial half of FDPb). Ant Interrosseous nv arise from median nv as it passess between 2 heads of PT

- Runs infront of Interrosseous membrane- supplies Deep flexors:- Lat ½ of FDP, FPL & PQ

- Supplies jointsDistal Radio- Ulnar joint Radio- Carpal jointCarpal joints

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MEDIAN NERVE: BRANCHES

Forearm cont’d

2. ARTICULAR - Elbow joint- Proximal R- U joint

3. PALMAR CUTANEOUS – Given proximal to flexor

retinaculum– Passes over retinaculum. Supplies

– central palm, – Skin thenar eminence,

4. COMMUNICATING Frequently present.

To ulnar nerve.

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MEDIAN NERVE: BRANCHESIN HAND1. Recurrent branch

• recurrent branch – supplies Thenar muscles

2. Lateral branch / Main Nerve – Lateral branch divides into

• 3 proper palmar digital branches.

Supply: 1. skin of thumb 2. Lat side of index finger. 3. Supplies msls:

• 1st lumbrical.

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MEDIAN NERVE: BRANCHES

2. Medial branch– Divides into

• two common palmer digital nerves.

• These further divide intoProper palmer digital nerves

Supply: 1. Sides of index, middle & half

of ring fingers.2. 2nd lumbrical

summary• All proper palmar digital nerves reach

on dorsum of Hand to supply nail beds and palmar aspect of lateral 3 ½ fingers

• Lateral two lumbricals supplied by Median

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MEDIAN NERVE: BRANCHES

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MEDIAN NERVE: CUTANEOUS INNERVATION

PALM

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MEDIAN NERVE: CUTANEOUS INNERVATION

DORSUM OF HAND- short of nailbeds

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MEDIAN NERVE - APPLIED

• Median Nerve Injury At Elbow

• Carpal Tunnel Syndrome

• Pronator Syndrome

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MEDIAN NERVE INJURY AT ELBOW

• All muscles paralyzed except FCU & FDP (medial half)

• MOTOR LOSS1. FDS & FDP ( LAT. HALF) –

• Loss of flexion at MP & IP Jts (OCHSNER’S CLASPING TEST – When patient asked to clasp the hands, index finger of affected side

fails to flex – remains as Pointing Index Finger)

2. FCR - • Loss of flexion of wrist• Ulnar deviation on attempts of flexion of wrist.

3. FPL - • Inability to flex terminal phalanx of thumb.

4. PQ and PT – pronation lost

5. Thenar eminence : muscles of thenar region affected – • Flattening of eminence. • Ape like hand• Abductor Pollicis Brevis and Opponens Pollicis– Paralysis.

(PEN TEST : Hand laid flat on table. Patient asked to touch a pen kept at slightly higher level than palm with the thumb)

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MEDIAN NERVE INJURY AT ELBOW

INJURY RESULTS IN1. Loss of pronation :

• PT & PQ

2. Loss of powerful flexion at wrist : • FCR & FDS (wrist deviates to ulnar side)

3. Loss of flexion of PIP of all digits : • FDS is paralyzed

4. Loss of flexion of DIP & MCP Joints of index and middle fingers

• FDP – lat. ½ &• Lumbricals 1st , 2nd paralyzed)

5. Loss of flexion, abduction & opposition of thumb :• Thenar muscles paralyzed

Thumb in adducted & extended position : APE LIKE HAND

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CARPAL TUNNEL SYNDROMEMost common entrapment mononeuropathy

Incidence - • females over 50 years.• 50% cases B/L. Mostly in dominant

hand.

Cause -

• Compression of Median nerve in fibro- osseous tunnel beneath flexor retinaculum.

Tunnel may be narrowed by a) Arthritic changes in wrist joint (RA) b) Anterior dislocation of Lunate /

complication of Colle’s fracture c) Soft tissue thickening in

Myxoedema & Acromegaly d) Oedema, Obesity, Pregnancy

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CARPAL TUNNEL SYNDROME

Symptoms

1. impairment of finer movements • (sewing, knitting, picking a pin)

2. paresthesia - • attacks of pain, tingling & numbness of radial 3

½ digits of affected hand. • wakes patient at night.

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CARPAL TUNNEL SYNDROME cont’d

On examination

– Wasting Of Thenar Eminence – • Muscle affected: AbPB & OP

– Hypo aesthesia – • palmar aspect of radial 3 ½ digits. • skin over thenar eminence and palm not affected

– as it is supplied by palmar cutaneous br of median N which arise proximal to carpal tunnel.

– Tinel’s Sign – • Percussion of Median nerve gently at wrist

– causing tingling sensation radiating into hand.

Tinel’s

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CARPAL TUNNEL SYNDROME cont’d

• Wrist Flexion Test (Phalen’s Sign) – • Exacerbation of symptoms when patient is asked to flex

wrist. Symptoms disappear as wrist straightened.

surgical treatment – – Carpal tunnel release.– Partial or complete division of flexor retinaculum

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Thenar atrophy

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PRONATOR SYNDROME.

• Uncommon entrapment neuropathy of Median Nerve

• Anatomical basis– Deep to Biceps aponeurosis– Between two heads of Pronator Teres– Through a fibrous arch of Flexor Digitorum Superficialis

• Clinical Features:1. Pain & tenderness

• in proximal aspect of anterior forearm.

2. Weakness of all muscles innervated by Median nerve. • Including Abductor Pollicis Brevis & long finger flexors.

3. Sensory impairment on palm of hand.

ULNAR NERVE

ULNAR NERVEFORMATION

- Branch of Medial cord.

- One of the terminal branch.

- Supplies small muscles in hand that are involved in fine intricate hand movements

- Called MUSICIAN’S Nerve.

ROOT VALUE:- (C7) C8-T1- C7- contribution from median N (lat

cord)

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ULNAR NERVE : COURSE

Axilla

• Forms in Axilla.

• Runs on medial side of axillary artery

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ULNAR NERVE : COURSE

arm

• runs medial to Brachial Artery till middle.• Pierces IM septum & • enters posterior compartment.• Descends in front of medial head of Triceps along

superior ulnar collateral artery (br of Brachial Art)

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Ulnar nerve medial to artery

Enters posterior compt by piercing medial IM septum

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Ulnar nerve lies infront of medial head of triceps

and then behind the medial epicondyle

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ULNAR NERVE : COURSE

elbow• lies in a groove on

dorsal aspect of medial epicondyle • interval bt medial

epicondyle and olecranon process.

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ULNAR NERVE : COURSE

forearm• Enters forearm

• bt humeral & ulnar heads of FCU (Cubital Tunnel)

• Runs downwards • in medial side of forearm.

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COURSE

• Rest on • FDP and under cover of FCU. • Ulnar artery is radial to nerve.

• Gives palmar cutaneous

(hypothenar eminence)and dorsal branch

• Enters palm by passing over flexor retinaculum 50

Ulnar N rest on FDP undercover of FCU which has been removed here

ULNAR NERVE : COURSE

wrist• enter palm by passing over

flexor retinaculum. • Ulnar N lies lateral to

pisiform and • medial to hook of hamate.• Ulnar art is lateral to

Nerve

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COURSE

• Both are bridged over • by a slender band of fibrous

tissue (superficial part of retinaculum)volar carpal lig

• forming a canal – GUYON’S CANAL.

Palm• In palm it passes deep to

Palmaris brevis • and divides into

• superficial & • deep branches. 52

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In palm it passes deep to Palmaris brevis

Right palm

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Ulnar N lies lateral to pisiform and medial to hook of hamate.

Right palm

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Right palm

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ULNAR NERVE : COURSE IN PALM

Superficial branch – • supplies

• Palmaris Brevis & • skin on medial 11/2 side of hand.

• Divides into • 2 palmar digital nerves • can be compressed against hook of

hamate• 1st palmar digital branch –

• medial side of little finger

• 2nd palmar digital branch – • adjacent sides of little & ring

fingers 57

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ULNAR NERVE : COURSE IN PALM

Deep branch – • Passes bt

• Abductor & Flexor digiti minimi and

• then bt • Opponens Digiti Minimi & 5TH Metacarpal.

• Follows course of deep palmar arch deep to flexor tendons.

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Supplies : 1. Hypothenars , 2. Interossei – dorsal and

palmar 3. Lumbricals 3rd & 4th4. Adductor Pollicis (at

times Flex Poll Brevis)

• Ends by supplying Adductor Pollicis – Grave yard

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Ulnar N

Deep branch entering bt abductor digiti minimi and flexor digiti minimi

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Passes bt Abductor & Flexor digiti minimi

and

then bt Opponens Digiti Minimi & 5TH Metacarpal.

Right palm

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ULNAR NERVE : Branches1. ARTICULAR

a) Elbow jointb) Wrist jointc) Small joints of hand-

– intercarpal and – carpometacarpal joints

2. CUTANEOUSa) Palmar cutaneous branch :

• Skin of hypothenar eminenceb) Dorsal branch :

• Dorsal 1 ½ digits (medial) on dorsum of hand

3. MUSCULAR AT FOREARMa) FCUb) FDP (med. Half) 63

4. TERMINALa) Superficial branch :

• Supplies Palmaris Brevis & medial 1 ½ digitsb) Deep branch : (muscular)

Suppliesa. Hypothenars :

• Ab Digiti Minimi, • Flex Digiti Minimi, • Opponens Digiti Minimi

b. Interossei : • All 4 Dorsal & 4 Palmar

c. Lumbricals : • 3rd & 4th (medial two)

d. Thenar : • Adductor Pollicis & Flex. Poll. Brevis (sometimes)

5. VASCULARVascular twigs to Axillary, Brachial, Ulnar and Deep palmar arch.

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MUSCLES SUPPLIED IN FOREARM

These muscles are primarily flexors of the wrist and fingers

FCUFDP (Med.half)

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MUSCLES SUPPLIED IN FOREARM

FCUFDP (Med. half)

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MUSCLES SUPPLIED IN HAND

Palmar aspect

Dorsal aspect

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ULNAR NERVE: CUTANEOUS INNERVATION OF HAND

SUPERFICIAL BRANCH OF RADIAL

PALM DORSUM

MEDIANULNAR

ULNAR

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LESIONS OF ULNAR NERVE

1. AT THE WRIST

• Ulnar nerve may be compressed in • Guyon's canal or • deeply thro msl of hypothenar eminence• trough formed by pisiform medially and

hook of hamate laterally• Tight pisohamate lig

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• Preservation of • FDP to ring and little fingers.• Dorsal cutaneous branch and palmar branch of Ulnar

nerve are spared – • lesion is distal to their origin from main trunk of

Ulnar nerve in forearm

• Lesion of • Superficial (to digits) and deep branches (intrin msls)

• Presentation

• Ulnar claw hand (medial two fingers are extended at MCP jt and flexed at the IP jt.

• Hypo aesthesia medial 1 ½ fingers 70

LESIONS OF ULNAR NERVE

2. AT THE ELBOWUlnar nerve lesion due to :

1. vulnerable position – • lies between medial epicondyle & olecranon: • lies on bone covered only by a thin layer

of skin. • Easily damaged if ulnar groove is

shallow.

2. Cubital tunnel syn• Entrapment neuropathy bt two heads of FCU

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LESIONS OF ULNAR NERVE

Presentation

• Weakness of FDP • affect ring & little fingers. • Produce ulnar claw hand with straighter fingers • Called “ulnar paradox” – lower lesion has more claw

feature

• All intrinsic msls of hand and sensations lost• Radial deviation of wrist on flexion

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LESIONS OF ULNAR NERVE

3. HAND

• Deep motor branch of Ulnar nerve compressed against pisiform & hamate

• - When hand is used as a mallet, or if a vibrating tool or motorcycle handlebar is held in such a way that Hypothenar eminence is off the edge of the handle.

• Sensory branches are always spared.

• involvement of hypothenar muscles is variable. (depends on the level at which branches to these muscles arise)

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Ulnar claw hand with lesion at wrist

FDP spared

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Ulnar claw hand

FDP affected – lesion higher level

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True claw hand – due to lesion of ulnar and median N

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RADIAL NERVE

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RADIAL NERVE

Nerve of Extensors of - arm - forearm Sensory to

- back of arm- back of forearm- dorsum of hand

FORMATION:-

•continuation of Posterior Cord• Root value: C5-C8 & T1• Largest branch of Brachial Plexus

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RADIAL NERVE: COURSE

Descends –behind 3rd part of

Axillary artery & –later behind

brachial art.

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In axilla

anterior toSubscapularis & tendons of LD & T Major

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Leaves axilla

thru triangular space along withProfunda brachii

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arm

At first Lies bt long & medial heads of Triceps.

Passes obliquely and enters spiral groove across post surf of humerus bt lateral & medial heads of Triceps. Here it covered by lat head.

Enter anterior compartment

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Showing relation of radial nerve to humerus and vessels

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RADIAL NERVE: COURSE con’td

Descends – bt Brachialis &

Brachioradialis (proximally)– and ECRL (distally)

Anterior to lateral Epicondyle- – Divides into terminal branches:

a) Superficial branch b) Posterior

Interosseous nerve (Deep br)

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Ant. to lat. Epicondyle –

Divides into terminal branches :•

Post. Interosseous nerve (Deep branch)

• Superficial branch

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Superficial branch

– descends along radial border of forearm.

– Crosses anatomical snuff box

– Reach back of hand

– Sensory to • dorsum of hand (lat.

2/3rd)• small area over palm.• Lateral 3 1/2 fingers

short of nail beds

Flexor aspect

Anatomical snuff box

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Deep branch

– Pierces Supinator

– enters extensor Compt of forearm.

Flexor aspect

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Deep branch

Supplies extensors of forearm.

SupinatorECRB, (BR, ECRL??)ED, EDM,ECU,

AbPL, EPB, EPL, EI

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RADIAL NERVE: REGION WISE BRANCHESIN AXILLA ( 2 muscular & 1 cut) 1. Post Cutaneous N of arm 2. A br to long head of triceps 3. A br to medial head of triceps

IN SPIRAL GROOVE (muscular, cut & articular)

1. Lower lat cut N of arm2. Post cut N of forearm3. Lateral & medial head of

triceps ANCONEUS, articular twigs to the elbow jt.

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Branches to triceps

Triceps supplied by 4branches from radial N. • Medial head : 2 br, • long head : 1 br, • lateral head : 1 br

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BEYOND RADIAL GROOVE ( in the lower part of arm)

(Above lateral Epicondyle)

– Brachialis Lateral part– Brachioradialis– Extensor Carpi Radialis

Longus (ECRL)– Elbow joint

– Then it divides into two branches

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RADIAL NERVE: REGION WISE BRANCHES

IN CUBITAL FOSSA1. Posterior

interosseous nerve (Deep branch)

2. Branch to Supinator3. Superficial br-

• supply • skin of lat side of

dorsum of hand and • dorsum of lat 3 ½

fingers proximal to nail beds.

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RADIAL NERVE: BRANCHES

Branches1. Muscular2. Cutaneous3. Articular

1. Muscular• Long, medial and lateral head of triceps• Anconeus• Extensor muscles

2. Cutaneous branch• Posterior cut N of arm• Lower lateral cut N of arm• Posterior cut N of forearm• Superficial br of radial (terminal)

3. Articular br• Elbow jt• Wrist and intercarpal

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RADIAL NERVE : APPLIED

studied under

1. Injury to N in axilla

2. Injury of N in spiral groove

3. Injury of Deep branch – Post interosseous N

4. Injury to superficial br

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RADIAL NERVE : APPLIED

1. Injury at axilla• Causes

1. Extra long crutches (CRUTCH PALSY)2. Fracture dislocation of upper humerus3. During reduction of shoulder dislocation

• Symptomsa) Motor:

– All extensors of wrist, elbow, finger paralyzed. Unopposed action of flexors

– WRIST DROP – Fingers can be extended (extension of IP jts) –

• done by lumbricals and interosseous (supplied by median/ulnar N)

– Inability to grip objects firmly. • (flexors working with decreased mechanical advantage, b’coz extension at wrist

is essential for stretching prior to flexion of digits)

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WRIST DROP unopposed action of flexors at wrist and elbow.

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WRIST DROP unopposed action of flexors at wrist and elbow.

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RADIAL NERVE : APPLIED

b) Sensory– Loss of sensation over

• posterior surface of arm, forearm and • lower lateral surface of arm

– Hand – dorsum lateral part– Digits – lateral 31/2 digits upto nail beds, dorsal

surface

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Sensory loss in radial nerve injury

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RADIAL NERVE : APPLIED

2. Injury of N in Spiral groove

• Causes– Fracture of middle shaft of humerus– Pressure on Nerve – Saturday Night palsy– Operating table edge– Prolonged use of tourniquet

a) Motor– Triceps not affected, WHY ???

• Extension of elbow not impaired– WRIST DROP

b) Sensory– Back of forearm, – dorsum of hand- lateral part– Digits – lateral 31/2 upto nailbed

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RADIAL NERVE : APPLIED

3. Injury to Deep br – Posterior interosseous N

• Causes– Fracture of upper radius– Dislocation of head of radius– Penetrating wound of upper forearm

• Motor– Brachioradialis, ECRL escapes injury.– Other extensors paralyzed– Effect at wrist :

• Extension possible but with radial deviation • ( be’coz ECRL escapes injury, ECU, ECRB paralyzed)

• No sensory loss– (Deep br purely motor)

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RADIAL NERVE : APPLIED

4. Injury at Superficial br• Superficial br superficially present on wrist

• Causes– Compression by

• Tight bracelets, watch straps, plaster casts, hand cuffs etc

a) No motor lossb) Sensory loss

– Hand – dorsum lateral ½– Digits – dorsum lateral 31/2 up to nail beds– Sensory loss may be minimal and may present only on dorsum of knuckle

of index finger

Summary – If triceps paralyzed – injury at axilla– BR paralyzed with normal triceps – injury at radial groove– If BR and triceps both normal – injury beyond lateral epicondyle

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